1. Technical Field
The present invention relates to an improvement in a developer-controlling member for controlling the amount of toner to be supplied to a latent image carrier, facing a developing roller for supplying the toner toward the latent image carrier while absorbing the toner by a magnetic force of a magnet roller. Furthermore, the present invention relates to a method for manufacturing the developer-controlling member, a developing machine using the same, an image forming apparatus or a printer such as a copy machine, facsimile and the like using the developing machine, and a jointed plate.
2. Related Art Statement
Conventionally, an image forming apparatus or printer has been provided with a developing machine including a developing roller for absorbing magnetic carrier and toner by a magnetic force of a magnet roller to supply the toner toward a latent image carrier, and a developer-controlling member (developing doctor) facing the developing roller, for controlling the amount of toner to be supplied to the latent image carrier (for example, reference to Japanese Patent Laid-Open 2000-98738).
This type of developing machine is used for a color copy machine, for example. The developing machine comprises a developing roller 1 and a developer-controlling member 2 as shown in FIGS. 1, 2. The developing roller 1 and the developer-controlling member 2 are provided in a developing casing (not shown).
The developing roller 1 includes a developing sleeve 3 and a magnet roller 4. The developing sleeve 3 and the magnet roller 4 are integrally rotated by a driving shaft 5.
The developer-controlling member 2 comprises a nonmagnetic plate 6 as a controlling plate and a magnetic plate 7 as a holding plate. The magnetic plate 7 is mounted onto the nonmagnetic plate 6. While developer 9 comprising magnetic carrier and toner is absorbed to the developing roller 1 by a uniform magnetic field generated between the magnet roller 4 and the magnetic plate 7, the developer 9 is supplied toward a photoconductor drum 11 as a latent image carrier.
In the nonmagnetic plate 6, a ridge line 10 faces the outer circumference of the developing sleeve 3. A gap G is formed between the sleeve 3 and the ridge line 10. The ridge line 10 of the nonmagnetic plate 6 has a role for controlling the supply of the absorbed developer 9 in order to stabilize an image quality.
Moreover, in the developer-controlling member 2, the holding plate and controlling plate comprise a metal plate, respectively. As a method for mounting the controlling plate onto the holding plate, there has been known a method for forming a fitting projection on the holding plate by half-blanking the holding plate, forming a fitting hole on the controlling plate, and holding after positioning the controlling plate onto the holding plate (for example, Japanese Patent-Laid-Open H08-160742).
Meanwhile, in order to uniform the supply of the toner 9 by the developer-controlling member 2, a constant gap G is necessary in the longitudinal direction of the developing roller. Therefore, the straightness of the ridge line 10 of the nonmagnetic plate 6 is required. In this case, the straightness is linearity in the longitudinal direction of the ridge line 10 of the nonmagnetic plate 6. As shown in FIG. 3, the straightness is evaluated by using the amount of irregularity Δ L with respect to the reference point O of the point P1 that the straight line L1 included in the plane S1 having the ridge line 10 of the nonmagnetic plate 6, and in the direction orthogonal to the extending direction of the ridge line 10 intersects with the ridge line 10.
In the invention disclosed in the Japanese Patent Laid-Open H08-160742, the supply of the developer 9 can be uniformed by the developer-controlling member 2. However, it is necessary to conduct a screw fastening operation when mounting the controlling plate onto the holding plate, so that an assembly operation is not effectively conducted. When the holding plate comprises the nonmagnetic plate 6 and the controlling plate comprises the magnetic plate 7, the assembly operation is not also effectively conducted.
As an operation for mounting the magnetic plate 7 onto the nonmagnetic plate 6, there has been known various means such as spot welding, YAG laser welding and bonding in addition to the above operation. However, it is difficult for the mounting operation by the spot welding to ensure the straightness because of the generation of the welding strains. Therefore, it is difficult to correspond to an image forming apparatus requiring a high image quality.
In the mounting operation by the YAG laser welding means, it is easy to correspond to the image forming apparatus requiring a high image quality because the welding strains are less; however, an installation cost is high. In addition, the welding is conducted by providing a plurality of welding points spacing in the longitudinal direction of the nonmagnetic plate 7, so that the welding operation is not effectively conducted.
In the mounting operation by the bonding means, it is necessary to perform various controls regarding adhesive agent, manufacture of a bonding jig, bonding time and the like. Therefore, it is not effective from the aspect of endurance and time.